Haque Emdadul, Shirasawa Kenta, Suematsu Keisuke, Tabuchi Hiroaki, Isobe Sachiko, Tanaka Masaru
Kyushu Okinawa Agricultural Research Center, National Agriculture and Food Research Organization, Miyakonojo, Japan.
Department of Frontier Research and Development, Kazusa DNA Research Institute, Kisarazu, Japan.
Front Plant Sci. 2023 Jun 5;14:1181909. doi: 10.3389/fpls.2023.1181909. eCollection 2023.
Given the importance of prioritizing genome-based breeding of sweet potato to enable the promotion of food and nutritional security for future human societies, here, we aimed to dissect the genetic basis of storage root starch content (SC) when associated with a complex set of breeding traits including dry matter (DM) rate, storage root fresh weight (SRFW), and anthocyanin (AN) content in a mapping population containing purple-fleshed sweet potato. A polyploid genome-wide association study (GWAS) was extensively exploited using 90,222 single-nucleotide polymorphisms (SNPs) obtained from a bi-parental 204 F population between 'Konaishin' (having high SC but no AN) and 'Akemurasaki' (having high AN content but moderate SC). Through the comparison of polyploid GWAS on the whole set of the 204 F, 93 high-AN-containing F, and 111 low-AN-containing F populations, a total of two (consists of six SNPs), two (14 SNPs), four (eight SNPs), and nine (214 SNPs) significantly associated signals were identified for the variations of SC, DM, SRFW, and the relative AN content, respectively. Of them, a novel signal associated with SC, which was most consistent in 2019 and 2020 in both the 204 F and 111 low-AN-containing F populations, was identified in homologous group 15. The five SNP markers associated with homologous group 15 could affect SC improvement with a degree of positive effect (4.33) and screen high-starch-containing lines with higher efficiency (68%). In a database search of 62 genes involved in starch metabolism, five genes including enzyme genes , , , and , and one transporter gene were located on homologous group 15. In an extensive qRT-PCR of these genes using the storage roots harvested at 2, 3, and 4 months after field transplantation in 2022, , which encodes the starch synthase isozyme that catalyzes the biosynthesis of amylose molecule, was most consistently elevated during starch accumulation in sweet potato. These results would enhance our understanding of the underlying genetic basis of a complex set of breeding traits in the starchy roots of sweet potato, and the molecular information, particularly for SC, would be a potential platform for molecular marker development for this trait.
鉴于优先开展甘薯基因组育种对于促进未来人类社会的粮食和营养安全至关重要，在此，我们旨在剖析在一个包含紫肉甘薯的作图群体中，贮藏根淀粉含量（SC）与包括干物质（DM）率、贮藏根鲜重（SRFW）和花青素（AN）含量在内的一系列复杂育种性状相关联时的遗传基础。利用从‘小根新’（SC高但无AN）和‘赤村崎’（AN含量高但SC中等）之间的双亲204个F群体获得的90,222个单核苷酸多态性（SNP），广泛开展了多倍体全基因组关联研究（GWAS）。通过对204个F、93个含高AN的F和111个含低AN的F群体的多倍体GWAS比较，分别鉴定出总共两个（由六个SNP组成）、两个（14个SNP）、四个（八个SNP）和九个（214个SNP）与SC、DM、SRFW和相对AN含量变异显著相关的信号。其中，在第15同源群中鉴定出一个与SC相关的新信号，该信号在2019年和2020年的204个F和111个含低AN的F群体中最为一致。与第15同源群相关的五个SNP标记可在一定程度上以正向效应（约4.33）影响SC的改良，并能更高效地筛选出高淀粉含量的品系（约68%）。在对62个参与淀粉代谢的基因进行数据库搜索时，包括酶基因、、、和以及一个转运蛋白基因在内的五个基因位于第15同源群上。在2022年田间移栽后2、3和4个月收获的贮藏根上对这些基因进行广泛的qRT-PCR分析时，编码催化直链淀粉分子生物合成的淀粉合酶同工酶的在甘薯淀粉积累过程中最持续上调。这些结果将增进我们对甘薯淀粉根中一系列复杂育种性状潜在遗传基础的理解，而这些分子信息，特别是关于SC的信息，将成为该性状分子标记开发的潜在平台。
